1. Field of the Invention
The present invention relates to a silver halide color photosensitive material with high sensitivity and excellent in preservation stability in the lapse of time, pressure property, grain size and radial rays resistance.
2. Description of the Related Art
As one of the high sensitization technologies of a silver halide photograph photosensitive material, the use of compounds called as “a one photon and two electrons type sensitizer” has been known, and such compounds are disclosed in, for example, the patent literatures 1 to 6. Further, as a technology by which higher sensitization than the use of “a one photon and two electrons type sensitizer” is obtained, compounds called as “a sensitizer capable of discharging one photon and three electrons or more” have been known, and such compounds are disclosed in, for example, the patent literatures 7 to 10 and 15.
On the other hand, it is disclosed in the patent literatures 11 and 12 that a silver halide color photosensitive material with high sensitivity and having little fog fluctuation is obtained by containing “a sensitizer capable of discharging one photon and two electrons or more” and a specific magenta coloring coupler, or a specific surfactant or the like.
However, although the inventors have tried to obtain the high sensitization of a silver halide color photosensitive material by prior arts described in the above patent literatures, they found that the following problems occur. Namely, there is a problem that although a photosensitive material using the compounds of “a one photon and two electrons type sensitizer” or the compounds of “a sensitizer capable of discharging one photon and three electrons or more” obtains the high sensitization just after coating, the high sensitization is greatly reduced in the lapse of time when the photosensitive material is preserved under a high temperature and high humidity for a short period or a long period. Further, pressure property which can be satisfied as photograph performance has also been not obtained.
A technical content prescribing “one photon and two electrons type sensitization by an electron donating compound (FED) which can be fragmented” and a sensitizing dye species is described in the patent literature 13. The technical content in the patent literature is that the lowering of blue sensitivity caused by combination with a blue dye with a longer wavelength is prevented by use in combination with the FED compound for faithful color reproducibility. However, the effect of the pressure property at using the sensitizing dye species in combination with FED is not disclosed, and satisfactory performance has been not obtained with respect to the pressure property by use of FED in combination with the blue dye which was disclosed.
By the way, an “earth-friendly” product has been strongly required in the industrial world from the viewpoint of environmental problem recently. Consequently, the industrial world is concentrated in preparation of the “earth-friendly” product day and night from the viewpoints of resource saving and energy saving. A photosensitive material having the coating amount of silver as little as possible is desired from the viewpoint of resource saving also in the business world of the silver halide photograph photosensitive material.
The development of the silver halide photograph photosensitive material having the coating amount of silver as little as possible has been already carried out by many approaches, and their technical contents are described in, for example, the patent literatures 14 and 15. In particular, it is disclosed in the patent literature 14 that radial rays resistance is improved by using a high sensitive silver halide emulsion having ISO speed of 800 or more at the coating amount of silver of 9.0 g/m2 or less and 3.0 g/m2 or more. However, the disclosure of lowering the content of silver and an effect of improving the radial rays resistance at that time using the high sensitization by “a compound capable of discharging one photon and two electrons to three electrons or more” as the original material are not described in these literatures.
On the other hand, a problem has been cleared that the higher the sensitivity is improved, the greater the deterioration of photograph performance due to long-term storage is. In particular, it has been a great problem in a negative color photosensitive material having the ISO speed of 400 or more. The cause of the deterioration of photograph performance due to long-term storage is a cause by natural radial rays (environmental radial rays and cosmetic rays) in addition to heat and humidity which have been well known, and a photosensitive material exposed to natural radial rays causes the increase of fog density and the deterioration of grain property in accordance with the increase. As a measure for deterioration of photograph performance by natural radial rays, a method of reducing the coating amount of silver (the above patent literature 14), a method of reducing the content of potassium in a photosensitive material (the patent literature 16) and the like have been known. As the method of reducing the radial rays fog, a method of adding a methylocyan dye (the patent literature 17), and a method using a compound other than gold chloride as a gold sensitizer (the patent literature 18), and a method of forming development initiation points on the same plane (the patent literature 19) are disclosed in addition to those literatures. However, these refer to only technologies for improving the sensitivity lowering and fog enhancement by radial rays, but do not clearly refer to a method of improving the grain size that deteriorates by radial rays. The disclosure of lowering the content of silver and an effect of improving the radial rays resistance at that time using the high sensitization by “a compound capable of discharging one photon and two electrons to three electrons or more” as the original material are not described in these literatures.
At all events, since the total coating amount of silver of the photosensitive silver halide is 6.0 g/m2 or less in terms of metal silver in the negative color photosensitive material having ISO speed of 400 or more, it has been difficult to realize a silver halide photosensitive material excellent in grain size and radial rays resistance.
Patent literature 1: U.S. Pat. No. 5,747,235
Patent literature 2: U.S. Pat. No. 5,747,236
Patent literature 3: EP 786692A1 (Compounds INV 1-35)
Patent literature 4: EP 893732A1
Patent literature 5: U.S. Pat. No. 6,054,260
Patent literature 6: U.S. Pat. No. 5,994,051
Patent literature 7: Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-) 2003-114487
Patent literature 8: JP-A-2003-114488
Patent literature 9: JP-A-2003-114486
Patent literature 10: JP-A-2003-140287
Patent literature 11: JP-A-2003-149776
Patent literature 12: JP-A-2003-149774
Patent literature 13: JP-A-2000-221628
Patent literature 14: Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 6-70710
Patent literature 15: U.S. Pat. No. 6,689,554
Patent literature 16: JP-A-2-836
Patent literature 17: JP-A-2-190851
Patent literature 18: JP-A-4-67032
Patent literature 19: JP-A-5-216246